The hospital didn't discover that the drive was missing until February 12, 2014.

Information on the drive includes last names, medical record numbers, birthdates, gestational ages, birth weights, dates of hospitalizations, and in some cases, transfer dates of children who were patients at either the Arnold Palmer Hospital for Children or the Winnie Palmer Hospital for Women and Babies between 2009 and 2013.

While the drive appears to have been lost and not stolen, and there's no indication that any of the information was accessed or used inappropriately, the hospital says it's contacting all affected families "as a precautionary measure."

"Arnold Palmer Medical Center takes this incident very seriously, and we are committed to protecting patients' health and personal information," Orlando Health corporate director of compliance and information security Steve Stallard said in a statement. "We deeply regret any concern or inconvenience this may cause."